Pyrin overexpression enhances IL-1β release in response to B. cenocepacia. (A) THP-1 cells, stably expressing YFP–pyrin, showed significantly higher inflammasome-dependent IL-1β release in response to B. cenocepacia compared with the control THP-1 cells. (B) Inflammasome-independent IL-8 release was similar between control and YFP–pyrin–overexpressing THP-1 cells infected with B. cenocepacia. (C and D) The same cells were infected with S. typhimurium for 4 h. There was no difference in IL-1β and IL-8 release between THP-1 varying in pyrin levels. Data are expressed as mean ± SD; n = 4 independent experiments. B.c., B. cenocepacia; NT, noninfected; S.t., S. typhimurium.